Vacuum tube



' Aug. 1935- F. OPPENHEIMER I 2,010,824

VACUUM TUBE Filed June 23, 1932 2 Sheets-Sheet l MW f Aug. 13, 1935. F.QPPENHEIMER VACUUM TUBE fined June 2:5, 1952 2 Sheets-Sheet 2 Faraflppejzlwwzer;

Patented Aug. 13, 1935 UNITED STATES PATENT OFFICE 12 Claims.

The present invention relates to electrical discharge devices, and moreparticularly to luminous vacuum tubes.

Among the objects of the present invention is to provide a novelluminous electrical discharge device which includes a vacuum tube havinga circulating or traveling gas or vapor therein.

Another object within the purview of the present invention is to soinfluence an electrical discharge within the electrode zone as toproduce any desired color efiect within the tube of the device.

At the present time, the lighting effects in the tubes of the typeherein disclosed are limited primarily to the natural color cliectsproduced by the neon, argon or helium gases, which are used asconducting gases within the tube of the discharge device, these inertgases being the preferred gases used in commercial signs and the like.Other lighting effects are obtained only by applying color to the glassof the tubes, which weakens the power and luminosity of the lightemanating therefrom. Metal vapors, principally mercury, have been usedfor producing various color effects, but metal vapors have a tendency toattack the tubes, thereby injuring the same and necessitating theirconstant replacement. Furthermore, a considerable amount of heat isrequired for vaporizing the mercury, and the vapors thereof enter thetube with the electrical discharges, thereby weakening the brilliancy ofthe light and sometimes giving the same a muddy appearance.

The present invention is therefore concerned with the idea of providinga novel luminous electrical discharge device in which a large variety ofcolors may be elfected by the use of metal vapors corresponding to thecolors, at the same time obtaining a moving light display, but resultsbeing obtained without decreasing the strength and intensity thereof andwithout substantially impairing or injuring the tubes of these devices.

The present invention also includes the idea of providing means foreffecting a circulation or movement of the conducting gas within thepassage of a vacuum tube, as well as means for bringing a metal vapor insufiicient quantity only in contact with the electrode emission ordischarge to give the desired color to the discharge and withoutintroducing these metal vapors into the circulating gas in sufficientquantitles to injure or damage the tube,

Still another object of the present invention is to provide a novelmethod for producing the lighting effects within the vacuum 'tube of aluminous electrical discharge device which in cludes the steps ofcreating movement or cir culation of a fluid body within the passage oithe vacuum tube whereby the conducting gaseou body within this vacuumtube is impelled thereby and caused to circulate within the passage ofthe tube. More particularly, the present invention contemplates the ideaof providing novel injector means including a condensable vapor, whichi.- caused to move or circulate for impelling the conducting gaseousbody within the vacuum tube when the same is brought into associationtherewith to cause a circulation of this gaseous body. this vapor beingcondensed outside the luminated zone of this conducting gaseous body.

The present invention also includes the idea of providing a novel methodfor producing any desired lighting effects within a luminous electricaldischarge device which includes the step of introducing limitedquantities of metal vapors into the electrode zone thereof to imparttheir color phase to the discharge, at the same time preventing all butlimited quantities of such vapors entering the tube circulation andthereby preventing substantial injury or damage to the tube.

A still further object of the present invention is to provide a novelmethod of producing varied light effects which includes the step ofintroducing limited quantities of metal vapors into a circulating bodyof conducting inert gas, whereby these lighting effects may be obtainedand without causing substantial injury or damage to the tube.

Other objects, features, capabilities, advantages and method steps arecomprehended by the invention, as will later appear and as areinherently possessed thereby.

Referring to the drawings:

Figure 1 is a view in elevation of a device made in accordance with thepresent invention;

Figure 2 is a view in elevation of another de vice made in accordancewith the present invention; and

Figure 3 is a broken view in elevation of still another device made inaccordance with the present invention.

Referring now more in detail to the drawings, an embodiment selected toillustrate the present invention is disclosed. in Figure 1 as comprisinga vacuum tube, generally referred to as 2, within which is disposedelectrodes 4 and B suitably connected, as by means of leads 8 and In, toa suitable source of electrical energy. The vacuum tube 2 is providedwith a passage l2 adapted to contain a conducting gas, as for exampleneon, helium, argon, krypton or xenon, which may be referred to asconducting gases of the noble gas group, and which may be commerciallyused in a luminous electrical discharge device of the type hereinreferred to. This vacuum tube may be circular, square, or rectangular incross section, as desired, and the same includes a portion I4 which,although disclosed as substantially oval in shape in Figure l of thedrawings, could be made in any desired configuration to provideornamental shapes, letters, numerals or other descriptive or artisticdecorations.

The passage of the portion I4 communicates, as by means of an outletpassage I6, with a tube portion I8 connected to a condensing bulb 20,which in turn communicates as by means of a passage 22 with the passageof the portion I4, this condensing bulb having a return 24 leading intothe lower portion of a receptacle 26 of an injector device or means 28.This injector means 28 further includes an ejector tube 30 leading fromthe top of the receptacle 26 which is formed with a Venturi-like endportion 32 projecting into the end of the tubular portion I8 adjacentthe passage I6.

Within the receptacle 26 is provided a suitable fluid body 34 adapted tobe vaporized as by means of heating coils 36, this medium 34, uponvaporization, passing upwardly through the tube 30 and Venturi-like endportion 32 and being discharged into the tube I8. The vaporized medium34 is caused to circulate through the tubular portion I8, therebyimpelling the conducting gas within the passage I2 of the tubularportion I4 in the direction as indicated by the arrow in this figure,the impelling of this conducting gas downwardly through the passage i6causing a circulation and movement of the same within the passage I2 ofthe tube portion I4. Adjacent the end of the Venturi-like portion 32,the conducting gas is caused to be associated with the vaporized medium34, and is carried therefrom toward the condensing bulb 20. At thatpoint, the vaporized medium 34 is condensed and is returned as by meansof the return 24 to the receptacle 26 to be vaporized again, and forproviding a continuous circulation of the same through the tube I8. Asthe vaporizing medium 34 is condensed in the bulb 20, the conducting gasfrom the passage I2 is impelled or forced through the inlet passage 22back into the passage I2 of the tube portion I4, suitable means 38, inthe form of coils or the like surrounding the passage 22, being providedto effect a complete condensation of the vaporized medium 34 and toeliminate the same from the conducting gas being introduced into thepassage I2. Although I have herein disclosed a pump of the vaporinjector type for creating circulation of the conducting gas within thevacuum tube of the present device, it is of course understood that othersuitable means may likewise be used within the scope of the presentinvention.

In the present embodiment, the medium 34 used in the injector means 28is disclosed as Butylpthalate oil. which has the advantage in a deviceof this kind in that the vapor thereof is inert and does not interferein any way with the conducting gas being impelled thereby. ThisButylpthalate oil is also to be preferred in a device of this kindbecause the same can be vaporized by the employment of very little heat,so that water cooling for condensing is not required, which would notonly be extremely objectionable in a device of this kind, but likewisewould add to the expense and inconvenience of installation.

In the present embodiment, the apparatus disclosed herein is preferablymade of glass, quartz or other suitable transparent material, and afterthe electrodes 4 and 6 have been installed in place and sealed, the airmay be pumped out of the tube so as to create as complete a vacuum aspossible preferably a vacuum of III millimeters Hg, which may beobtained by employing a molecular pump and which is measured with aFaraday cage. The electrodes may be prepared and installed as usual incommercial lamps, or preferably they should be of the type described inmy co-pending application Serial No. 618,863, filed June 23, 1932. TheButylpthalate oil may then be placed in the vaporizer or condenser 26 byany of the well-known methods of feeding liquids into vacuum tubes.After the oil has reached the desired level, the conducting gas which isto be used is fed into the tube portion I4 under just enough pressure tocreate the least resistance to the current used. After the tube isfilled with the gas, the current is applied to the heating coils 36,which heat the oil and cause the same to vaporize, thereby creating acirculation of this vaporized oil within the tube l8.

Simultaneously with the application of current to the heating coils 36,a circuit may be completed through the leads 8 and It! for theelectrodes 4 and Ii, whereby the electrodes will cause the emission ofelectrons through the tube to start the electron discharge through theconducting gas. The device will then operate to cause a continuousmovement of the conducting gas within the tube portion I4. It is ofcourse to be understood that any suitable means may be provided forcausing intermittent flow of electrical energy to the electrodes 4 and6, whereby the laminating effects are intermittent, and if desired, thepresent embodiment may be provided with suitable means whercby reversalof flow of the conducting gas within the passage I2 may be effected.

As previously indicated, the present invention is also concerned withthe idea of providing a luminous electrical discharge device ofbrilliant colors in which various luminating effects may be provided bymeans of metal vapors without substantial injury or damage to the tubeof the same. In Figures 2 and 3 is disclosed an embodiment made inaccordance with the present invention, wherein suitable metal vapors maybe introduced into the conducting gas to color the same as desired, thisembodiment comprising a vacuum tube, generally designated as 40, whichcomprises a tube portion 42 corresponding to the tube portion I4 of thehereinbefore described embodiment, and although disclosed as beingelongated and substantially straight, it is of course understood thatthe same may be formed to provide various ornamental shapes, letters,numerals or othere descriptive or artistic decorations. Adjacent one endof the tube portion 42 is a tube portion 44 within which is disposed anelectrode 46 having a lead passing outwardly through the tube portion 44which may be connected to a source of power 48. The vacuum tube 40 isalso provided with a portion 50 which extends downwardly, as shown, fromthe tube portion 42, and communicates with a tube portion 52, which inturn communicates with the condensing bulb 54. The present embodimentlikewise includes the idea of incorporating an ejector means 56corresponding to the ejector means 28, which comprises a vaporizer orreceptacle 58 provided with OLHI'iUH nuum a tube 60 formed with aVenturi-like end portion 62 inserted within the end of the tube 52adjacent the tubular portion 56. This receptacle 58 has a return 64leading into the same adjacent the bottom thereof from the lower part ofthe condenser bulb 5d, all of this structure being in accordance withthe corresponding structure shown in Figure l of the drawings.

Extending upwardly from the condensing bulb 5 3 is a tube portion 66which leads into a bulb or receptacle 68, this tube portion 66 having atube portion Ill concentrically arranged therein,

which communicates with the tube portion t2, the

tube portion 1!] leading into the receptacle 68 and forming an annularpassageway at the end of the tube portion 66 adjacent the receptacle orbulb 68. This bulb or receptacle 68 has a supply of metal l2 disposed inthe lower portion thereof and encloses an electrode 14 which has a lead16 extending therefrom to the source of power 18.

Disposed within the vacuum tube 4!] is con ducting gas which ispreferably of neon, helium,

argon, krypton or xenon, and this conducting gas is caused to circulateby the vaporization and condensation of thevaporizing material withinthe vaporizer 53,'this material, as in the hereinbefore referred toembodiment, being preferably Butylpthalate oil, which is vaporized bymeans of heating coils l8 and caused to condense in the condenser 54 andbe returned through the return 64 to the condenser 58, suitable coolingcoils being provided around the tube portion- 66 adjacent the condenser54 to provide for the con densation of any traces of this oil as theconducting gas passes upwardly through the tube portion 65.

Any desired metal 12 may be provided in the receptacle 68 for producingany desired color to the conducting gas. As for example, by using themetal strontium, brilliant red lighting efiects may be produced in thetube portion d2, while if barium metal is used, a vivid green light maybe effected, or if sodium is used, a brilliant yellow light may likewisebe obtained. Many other colors'may be secured by using the proper metalswithin the receptacle 68 corresponding to those colors which aredesired, and it is of course understood that the present inventionincludes the use of any metal to obtain the desired effects. It is alsounderstood that metals of varying vapor pressure will require higher orlower vacua and/ or more or less heat, which latter, if desired, may beobtained from an external source.

As previously indicated, coloring effects in a luminous electricaldischarge tube of the kind herein disclosed have been obtained only by acoloring of the tube itself, or otherwise applying color on the outsideof it. This has been necessary because of the fact that metal vapors introduced into the tubes have a great affinity for the same and attackand injure t-hese tubes, thereby necessitating constant replacement. Inthe present embodiment, however, the metal vapors within the bulb orreceptacle 68 and surrounding the electrode M are substantially allretained within this receptacle, inasmuch as the upward flow orcirculation of conducting gas through the tube portion 66 tends to pushor crowd these metal vapors away from the end of the entrance to thetube portion '10, whereby a very small amount of metal vapor isintroduced into the inner tube portion Ill for passage through thevacuum tube 40. The amount passing through the vacuum tube 40, however,is suificient to give the desired lighting efiects, yet not surfiof thetube portion 8 5.

shown in Figure 2 of the drawings, each of the cient to causesubstantial damage or injury to this vacuum tube.

It is of course understood that the bulbs may be so designed, and therate of vaporizing of the metal and the oil so controlled that thecirculation of the conducting gas in the tube 30 is controlled, and theamount of vaporized metal entering this vacuum tube suitably controlledto produce the desired efifect. The embodiment disclosed in Figure 2 ofthe drawings is particularly adapted for use in connection with lowvoltage sources of electrical energy, as likewise for use in directcurrent circuits. If desired, a suitable absorbing agent may be placedwithin the tube Ill or a retainer.interposed between the receptacle 68and tube portionAZ to absorb excess metal vapors. This absorbing agentmay be activated'carbon or any other desired substance.

In Figure 3 of the drawings is disclosed another embodiment made inaccordance with the present invention, particularly adapted for use withsources of electrical energy having high voltage and in devices of thekind in which a substantially long display tube is desired. Thisembodiment corresponds in all essentials to the embodiment shown inFigure 2 of the drawings, and includes a vacuum tube 82 which includes atube portion 84 corresponding to the tube portion 1-2 of Figure 2 of thedrawings. Associated with this vacuum tube is an ejector means 86 whichcorresponds with either of the ejector means heretofore disclosed, andcooperates with the vacuum tube in the same manner to cause acirculation of conducting gas within the vacuum tube 82. In the presentembodiment, however, the electrodes 88 and 90 are each disposed within areceptacle 92 and 94, respectively, adjacent the ends of the vacuum tube82, and are suitably connected as by means of leads 96 and 98 with asource of electrical energy. In this embodiment, the circulation of theconducting gas through the vacuum tube 82 is in a counter-clockwisedirection, and passes from the tube portion 84 into the tube portion MWat the end thereof, which is adapted to discharge into the receptacle 92and which is concentrically arranged within an outer tube portion N12which communicates with the receptacle 92, as likewise the tube ladconnected to the condenser bulb Hit of the ejector means 86. a

The conducting gas within the vacuum tube 82 is caused to circulate bymeans of the ejector means 86 and passes from the condenser Hi5 throughthe tube portion I08 merging with an enlarged tube portion H0 enteringthe receptacle 94 and concentrically arranged with an inner tube portionl l2 likewise communicating with the receptacle 9d and formed integralwith the end As in the embodiment receptacles or reservoirs 92 and 9-1has a source of metal H4 disposed therein, which is suitably vaporizedas by means of the electrodes 83 and 90, and in accordance with theabove disclosure, limited quantities only of these metal vapors gainentrance to the vacuum tube 82, these limited quantities, however, beingsufiicient to produce the lighting efiects desired without substantiallyinjuring or damaging the vacuum tube 82. An absorbing agent, such asactivated carbon or the like, may be used for absorbing excess metalvapors and to prevent passage thereof into the vacuum tube 82.

While I have herein described and upon the drawings shown anillustrative embodiment of the invention, it is to be understood thatthe invention is not limited thereto but may comprehend otherconstructions, arrangements of parts, details, features and method stepswithout de-- parting from the spirit of the invention.

I claim:

1. An electrical discharge device comprising a vacuum tube having aportion adapted to conform to any desired configuration and a portioncommunicating therewith to provide a continuous passage, a conductinggas in said tube, electrodes disposed in said tube and connected to asource of electrical energy, injector means for introducing a fluid bodyinto said second-named portion, and means for condensing said fluid bodyto effect a continuous circulation of said gas and to remove the samebefore entrance thereof into said first-named portion of said tube.

2. The method of circulating a gaseous body within an electricaldischarge tube, comprising the steps of causing movement of a fluidbody, directing said gaseous bodyv into the path of movement thereofwhereby the same is impelled, effecting a separation of said gaseous andfluid bodies, and directing said gaseous body into said tube beyond inthe normal direction of movement thereof.

3. A luminous electrical discharge device, comprising a vacuum tubehaving a passage containing a conducting gas, electrodes disposed insaid tube, a reservoir communicating with said passage and containing asupply of metal, one ofsaid electrodes being adapted to vaporize saidmetal, means for circulating said gas and vapor through said passage andmeans for limiting introduction of metal vapors into said passagewhereby the desired lighting effects are obtained without substantialinjury to said tube.

4. A luminous electrical discharge device, comprising a vacuum tubehaving a passage containing a conducting gas, electrodes disposed insaid tube, a reservoir disposed in an electrode zone and communicatingwith said passage, said reservoir containing a supply of metal adaptedto be vaporized by said electrode, means :[or circulating said gas andvapor through said passage, and means for limiting introduction of saidmetal vapor into said passage whereby the desired lighting effects areobtained Without substantial injury to said tube.

5. A luminous electrical discharge device, comprising a vacuum tub-ehaving a passage containing a conducting gas, said tube including ametal reservoir containing a supply of metal and communicating with saidpassage, electrodes disposed in said tube, one of said electrodes beingwithin said reservoir and being adapted to vaporize said metal, meansfor circulating said gas and vapor through said passage, and means forlimiting introduction of said metal vapor into said passage whereby thedesired lighting efiects are obtained Without substantial injury to saidtube.

6. A luminous electrical discharge device, comprising a vacuum tubehaving a passage containing a conducting gas, electrodes disposed insaid tube, means for causing circulation of said gas in said passage,said tube including a reservoir communicating with said passage andcontaining a supply of metal, means for vaporizing said metal, and meansfor limiting introduction of metal vapor into said passage to color saidgas and to give the desired lighting effects without substantial injuryto said tube.

7. A luminous electrical discharge device, comprising a vacuum tubehaving a passage contain ing a conducting gas, electrodes disposed insaid tube, means for causing circulation of said gas in said passage.said tube including a reservoir communicating with said passage andcontaining a supply of metal, one of said electrodes being disposedwithin said reservoir and being adapted to vaporize said metal, andmeans for limiting introduction of said metal vapor into said passagewhereby the desired lighting effects are obtained without substantialinjury to said tube.

8. An electrical discharge device comprising a vacuum tube having apassage, conducting gas in said passage, a reservoir containing avolatile material, said tube having ends in spaced relation inassociation with said reservoir whereby gas from said passage enterssaid reservoir, and means for effecting circulation of said gas.

9. An electrical discharge device comprising a vacuum tube having apassage, conducting gas in said passage, a reservoir containing avolatile material, said tube having ends associated with said receptacleand. in radial spaced relation whereby gas from said passage enters saidreservoir, and means for effecting circulation of said gas.

10. An electrical discharge device comprising a vacuum tube having apassage, conducting gas in said passage, a reservoir containing avolatile material, said tube having ends associated with. said reservoirand in radial and axial spaced relation whereby gas from said passageenters said reservoir, and means for eiiecting circulation of said gas.

11. A luminous electrical discharge device, comprising a vacuum tubehaving a passage containing a conducting gas, means for exciting saidgas comprising electrodes, means for causing circulation of said gas insaid passage, said tube including a reservoir communicating with saidpassage and containing volatile material, one of said electrodes beingdisposed within said reservoir, and means for passage of volatilematerial from said reservoir into the passage of said tube to obtaindesired lighting effects.

12. A luminous electrical discharge device, comprising a vacuum tubehaving a passage containing a conducting gas, means for exciting saidgas comprising electrodes, means for causing circulation of said gas insaid passage, said tube including a plurality of reservoirs eachcommunicating with said passage and containing volatile material, eachof said reservoirs containing an electrade and means for passage ofvolatile material from said reservoirs into the passage of said tube toobtain desired lighting effects.

FRANZ OPPENHEIMER.

